package PTA_JAVA.JavaBase.JavaBase28;

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);

        int n=sc.nextInt();
        double x=sc.nextDouble();
        double y=sc.nextDouble();
        n=(int)(n-(y/x));
        if(n<0){
            System.out.println(0);
        }else{
            System.out.printf("%d",n);
        }

    }
}
